Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

Gay Men Outraged Over Inability to Donate Blood For Shooting Victims

Gay men are angry over a federal law that bans them from donating blood to help their LGBT "brothers and sisters" wounded in the mass shooting at the Pulse nightclub in Orlando.

Under the Food and Drug Administration rules, men who have had sex with another man in the past 12 months are not allowed to donate blood, CNN reported.

Forty-nine people were killed and at least 53 other injured in the attack early Sunday morning.

The OneBlood donation center put out an urgent call for blood donors to help the injured, and more than 5,300 people donated blood through the OneBlood statewide network on Sunday. That was a single-day record, said Susan Forbes, OneBlood's vice president of of marketing and communications, CNN reported.

But that huge public response did not include gay and bisexual men because of the blood donation ban. Some expressed their frustration online by saying it's easier to buy a gun in the U.S. than for a gay man to donate blood.

There were conflicting media reports about whether the ban had been temporarily lifted, but OneBlood said in a tweet Sunday that all FDA rules were still in place, CNN reported.

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Nations Pledge to Double Number of HIV Patients Receiving Care

A promise to nearly double the number of people with HIV who receive treatment over the next five years was made by countries attending a United Nations conference on ending the global AIDS epidemic by 2030.

Countries also pledged to monitor the quality of HIV treatment in order to ensure that 90 percent of patients receive antiretroviral drugs to lower their viral load to an undetectable level, the Associated Press reported.

This is a major shift because it means for the first time the emphasis is on quality rather than just the number of patients receiving treatment, according to Sharonann Lynch, HIV & TB Policy adviser for Medecins Sans Frontiers.

About 36.7 million people worldwide have HIV, the AP reported.

The conference concluded Friday.

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Man Survives 555 Days Without a Heart

An American man lived 555 days without a heart while awaiting a transplant.

Stan Larkin's heart was removed from his body in November 2014 and replaced with a device that enabled the 25-year-old Ypsilanti, Michigan resident to remain at home while he waited for a new heart, CNN reported.

Larkin appeared normal but wore a backpack that housed the power source for the artificial heart pumping in his chest.

He finally received a new heart in May and is now recovering in hospital. He may return home as early as next week, CNN reported.

"Most people would be scared to go so long with [an artificial heart], but I just want to tell them that you have to go through the fear, because it helps you," Larkin said. "I'm going home so fast after the transplant because it helped me stay healthy before the transplant."

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FDA Approves Cholera Vaccine for U.S. Travelers

The first vaccine to protect American travelers from cholera has been approved by the U.S. Food and Drug Administration.

The liquid vaccine Vaxchora was approved for adults ages 18-64 who are traveling to countries affected by cholera, the Associated Press reported.

Cholera is a potentially life-threatening bacterial infection that is rare in the U.S. but still present in many parts of Africa, Southeast Asia and Haiti. Severe cases of cholera can cause intense diarrhea and vomiting, resulting in dehydration.

The FDA's approval of the vaccine is based on four clinical trials that included a total of nearly 3,800 people. Common side effects included abdominal pain, diarrhea, headache and fatigue, the AP reported.